1. Field of the Invention
The present invention relates to an imprint method for pattern forming in a semiconductor manufacturing process, and to a template for imprinting.
2. Description of the Related Art
In recent years, along with a progress of down-sizing of a semiconductor device, problems that may occur in a photolithography process used in the manufacturing process of the semiconductor device have become more apparent. That is, in the recent leading-edge rules for designing a semiconductor device based on half-pitch, a pitch size has been reduced down to 22 nm. However, with a conventional lithography technique where a miniaturized pattern is exposed to light, it is difficult to achieve resolution to the extent that complies with the latest design rule. Consequently, it has become difficult to form a miniaturized pattern to such an extent that meets the latest design rule. From this perspective, as disclosed in Japanese Patent Application Laid-Open No. 2001-68411, and Japanese Patent Application Laid-Open No. 2000-194142, for instance, a nano-imprint technique has been proposed as a patterning technique that can be an alternative to the lithography technique.
According to the nano-imprint technique, a master plate (i.e. a template) with a pattern to be printed being formed is pressed on an organic material having been applied on a substrate being a processing target. In such condition, the organic material is exposed to light, whereby the exposed organic material is to harden, eventually enabling the pattern to be printed in the organic material layer on the substrate. Therefore, according to the nano-imprint technique, variation factors such as focal depth, aberration, exposure amount, etc. which have been problems in the conventional lithography process can be reduced, as a result of which patterning can be executed simply and with high accuracy.
According to the nano-imprint technique, a desired pattern can be formed by repeating sequential patterning processes of applying the organic material, contacting the template and the organic material, and hardening the organic material, with respect to each pattern printing region. However, when a comparatively thick hardened organic material portion in the pattern printed region (also referred to as a shot) where the pattern has already been formed by the organic material being hardened extends into an adjacent shot as being a patterning target, downward movement of the template as performed in patterning of the adjacent shot lying next to the target shot may be interfered with the hardened organic material. When the downward movement of the template is interfered, the template and the organic material will not be able to contact sufficiently with each other in the pattern printing region as being a patterning target. As a result, printing deficiency may occur.
For this reason, in the conventional nano-imprint technique, in order to prevent the hardened organic material, where patterning has already been completed, from extending into the adjacent shot regions, gaps of several hundred micrometers are provided among respective shot regions. Therefore, the whole substrate surface cannot be used effectively for pattern formation, and the number of shots which can be formed on the substrate is to be limited.